Just to add to the thread, heres a summary of a Norovirus

Noroviruses are a group of viruses that cause the “stomach flu,” or gastroenteritis (GAS-tro-en-ter-I-tis), in people. The term norovirus was
recently approved as the official name for this group of viruses. Several other names have been used for noroviruses, including:
* Norwalk-like viruses (NLVs)
* caliciviruses (because they belong to the virus family Caliciviridae)
* small round structured viruses.
Viruses are very different from bacteria and parasites, some of which can cause illnesses similar to norvirus infection. Viruses are much smaller, are
not affected by treatment with antibiotics, and cannot grow outside of a person’s body.
What are the symptoms of illness caused by noroviruses?
The symptoms of norovirus illness usually include nausea, vomiting, diarrhea, and some stomach cramping. Sometimes people additionally have a
low-grade fever, chills, headache, muscle aches, and a general sense of tiredness. The illness often begins suddenly, and the infected person may feel
very sick. The illness is usually brief, with symptoms lasting only about 1 or 2 days. In general, children experience more vomiting than adults. Most
people with norovirus illness have both of these symptoms.

www.cdc.gov...
How serious is norovirus disease?
Norovirus disease is usually not serious, although people may feel very sick and vomit many times a day. Most people get better within 1 or 2 days,
and they have no long-term health effects related to their illness. However, sometimes people are unable to drink enough liquids to replace the
liquids they lost because of vomiting and diarrhea. These persons can become dehydrated and may need special medical attention. This problem with
dehydration is usually only seen among the very young, the elderly, and persons with weakened immune systems. There is no evidence to suggest that an
infected person can become a long-term carrier of norovirus.

[edit on 11/6/2004 by QuietSoul]